Development of a deep-learning algorithm for age estimation on CT images of the vertebral column.

PURPOSE: The accurate age estimation of cadavers is essential for their identification. However, conventional methods fail to yield adequate age estimation especially in elderly cadavers. We developed a deep learning algorithm for age estimation on CT images of the vertebral column and checked its accuracy. METHOD: For the development of our deep learning algorithm, we included 1,120 CT data of the vertebral column of 140 patients for each of 8 age decades. The deep learning model of regression analysis based on Visual Geometry Group-16 (VGG16) was improved in its estimation accuracy by bagging. To verify its accuracy, we applied our deep learning algorithm to estimate the age of 219 cadavers who had undergone postmortem CT (PMCT). The mean difference and the mean absolute error (MAE), the standard error of the estimate (SEE) between the known- and the estimated age, were calculated. Correlation analysis using the intraclass correlation coefficient (ICC) and Bland-Altman analysis were performed to assess differences between the known- and the estimated age. RESULTS: For the 219 cadavers, the mean difference between the known- and the estimated age was 0.30 years; it was 4.36 years for the MAE, and 5.48 years for the SEE. The ICC (2,1) was 0.96 (95 % confidence interval: 0.95-0.97, p < 0.001). Bland-Altman analysis showed that there were no proportional or fixed errors (p = 0.08 and 0.41). CONCLUSIONS: Our deep learning algorithm for estimating the age of 219 cadavers on CT images of the vertebral column was more accurate than conventional methods and highly useful.

Perioperative proximal splenic artery embolization in cirrhotic patients with splenomegaly.

INTRODUCTION: The purpose of this study was to determine the effect of proximal splenic artery embolization (SAE) in cirrhotic patients with splenomegaly who underwent surgical laparotomy. MATERIAL AND METHODS: This retrospective observational study included 8 cirrhotic patients with splenomegaly. They underwent proximal SAE before- (n = 6) or after (n = 2) laparotomy. Vascular plugs or coils were placed in the proximal splenic artery. The diameter of the portal vein and the splenic volume were recorded. Clinical outcome assessments included platelet counts, the model for end-stage liver disease (MELD) score, and complications. RESULTS: After embolization, the portal venous diameter was significantly smaller (pre: 13.6 ± 2.7 mm, post: 12.5 ± 2.3 mm, p = 0.023), the splenic volume was significantly decreased (pre: 463.2 ± 145.7 ml, post: 373.3 ± 108.5 ml, p = 0.008) and the platelet count was significantly higher (pre: 69.6 ± 30.8 × 103/µl, post: 86.8 ± 27.7 × 103/µl, p = 0.035). Before embolization, the median MELD score was 12; after embolization, it was 11 (p = 0.026). No patient developed post-treatment complications after embolization. CONCLUSIONS: The reduction of hypersplenism by perioperative proximal SAE may be safe and reduce the surgical risk in cirrhotic patients with splenomegaly.

Transportal scleroembolization of hepatic arterioportal fistulas in a patient with portal hypertension: A case report.

We report a rare patient with portal hypertension who presented with esophageal- and gastric varices and refractory ascites due to hepatic arterioportal fistulas. Treatment by transportal scleroembolization using ethanolamine oleate and coils were successful. Pretreatment hepatofugal flow subsequently changed to hepatopetal flow and the symptoms of portal hypertension improved. We describe our endovascular treatment option for addressing hepatic arterioportal fistulas.

Iodine maps derived from sparse-view kV-switching dual-energy CT equipped with a deep learning reconstruction for diagnosis of hepatocellular carcinoma.

Deep learning-based spectral CT imaging (DL-SCTI) is a novel type of fast kilovolt-switching dual-energy CT equipped with a cascaded deep-learning reconstruction which completes the views missing in the sinogram space and improves the image quality in the image space because it uses deep convolutional neural networks trained on fully sampled dual-energy data acquired via dual kV rotations. We investigated the clinical utility of iodine maps generated from DL-SCTI scans for assessing hepatocellular carcinoma (HCC). In the clinical study, dynamic DL-SCTI scans (tube voltage 135 and 80 kV) were acquired in 52 patients with hypervascular HCCs whose vascularity was confirmed by CT during hepatic arteriography. Virtual monochromatic 70 keV images served as the reference images. Iodine maps were reconstructed using three-material decomposition (fat, healthy liver tissue, iodine). A radiologist calculated the contrast-to-noise ratio (CNR) during the hepatic arterial phase (CNRa) and the equilibrium phase (CNRe). In the phantom study, DL-SCTI scans (tube voltage 135 and 80 kV) were acquired to assess the accuracy of iodine maps; the iodine concentration was known. The CNRa was significantly higher on the iodine maps than on 70 keV images (p < 0.01). The CNRe was significantly higher on 70 keV images than on iodine maps (p < 0.01). The estimated iodine concentration derived from DL-SCTI scans in the phantom study was highly correlated with the known iodine concentration. It was underestimated in small-diameter modules and in large-diameter modules with an iodine concentration of less than 2.0 mgI/ml. Iodine maps generated from DL-SCTI scans can improve the CNR for HCCs during hepatic arterial phase but not during equilibrium phase in comparison with virtual monochromatic 70 keV images. Also, when the lesion is small or the iodine concentration is low, iodine quantification may result in underestimation.

Understanding CT imaging findings based on the underlying pathophysiology in patients with small bowel ischemia.

Because acute small bowel ischemia has a high mortality rate, it requires rapid intervention to avoid unfavorable outcomes. Computed tomography (CT) examination is important for the diagnosis of bowel ischemia. Acute small bowel ischemia can be the result of small bowel obstruction or mesenteric ischemia, including mesenteric arterial occlusion, mesenteric venous thrombosis, and non-occlusive mesenteric ischemia. The clinical significance of each CT finding is unique and depends on the underlying pathophysiology. This review describes the definition and mechanism(s) of bowel ischemia, reviews CT findings suggesting bowel ischemia, details factors involved in the development of small bowel ischemia, and presents CT findings with respect to the different factors based on the underlying pathophysiology. Such knowledge is needed for accurate treatment decisions.

Cranio-caudal puncture with computed tomography-guided drainage of a deep pelvic abscess.

Purpose: Computed tomography (CT)-guided percutaneous drainage has been used to address pelvic abscesses because it is safe and minimally invasive. However, CT-guided drainage has the limitation that the puncture route should be on the same axial slice. A technique for puncturing in the cranio-caudal direction under CT fluoroscopy is needed. Case report: An 82-year-old man with an abscess due to rectal cancer was scheduled for CT-guided drainage to improve his general condition before radical surgery. Drainage was performed via a perineal approach to localize the drainage tract in the resection area to avoid dissemination of cancer cells. To perform a puncture in the cranio-caudal direction we controlled the needle like a joystick and advanced it under CT fluoroscopy while moving the CT gantry cranially to follow the needle tip throughout the puncture. Our unique technique yielded successful CT-guided puncture in the cranio-caudal direction. Conclusions: Our unique technique overcomes the limitations of CT-guided cranio-caudal puncture and may allow the drainage of abscesses whose treatment was heretofore difficult.

Global illumination rendering versus volume rendering for the forensic evaluation of stab wounds using computed tomography.

We compared three-dimensional (3D) CT images of stabbing victims subjected to volume-rendering (VR) or global illumination-rendering (GIR), a new technique now available for the reconstruction of 3D CT images. It simulates the complete interactions of photons with the scanned object, thereby providing photorealistic images. The diagnostic value of the images was also compared with that of macroscopic photographs. We used postmortem 3D CT images of 14 stabbing victims who had undergone autopsy and CT studies. The 3D CT images were subjected to GIR or VR and the 3D effect and the smoothness of the skin surface were graded on a 5-point scale. We also compared the 3D CT images of 37 stab wounds with macroscopic photographs. The maximum diameter of the wounds was measured on VR and GIR images and compared with the diameter recorded at autopsy. The overall image-quality scores and the ability to assess the stab wounds were significantly better on GIR than VR images (median scores: VR = 3 vs GIR = 4, p < 0.01). The mean difference between the wound diameter measured on VR and GIR images and at autopsy were both 0.2 cm, respectively. For the assessment of stab wounds, 3D CT images subjected to GIR were superior to VR images. The diagnostic value of 3D CT GIR image was comparable to that of macroscopic photographs.

Safety margin for CT- and US-guided radiofrequency ablation after TACE of HCC in the hepatic dome.

INTRODUCTION: We evaluated the safety margin in patients with hepatocellular carcinoma (HCC) in the hepatic dome who underwent computed tomography (CT)- or ultrasound (US)-guided radiofrequency ablation (RFA). MATERIAL AND METHODS: Included in this single-center study were 46 patients with 56 HCCs in the hepatic dome undergoing RFA after transarterial chemoembolization from January 2009 to December 2016. Thirty were addressed with CT fluoroscopy and 26 with US guidance. The technical success, safety margin, and local tumor progression (LTP) were evaluated. RESULTS: Technical success rate was 100% in the CT-RFA and 84.6% in the US-RFA group (p = .04). The average safety margin was 4.8 mm in the CT-RFA and 3.0 mm in the US-RFA group (p = .01). There was no LTP among the HCCs with a safety margin >3 mm achieved in 73.3% CT-RFA and 42.3% US-RFA group tumors (p = .03). Of the US-RFA group, six required additional RFA. There was no significant inter-group difference in LTP (p = .36). CONCLUSION: CT-guided RFA was superior to US-guided RFA with respect to the technical success rate and the acquisition of an appropriate safety margin in patients with HCC in the hepatic dome.

Accuracy of thin-slice model-based iterative reconstruction designed for brain CT to diagnose acute ischemic stroke in the middle cerebral artery territory: a multicenter study.

PURPOSE: Model-based iterative reconstruction (MBIR) yields higher spatial resolution and a lower image noise than conventional reconstruction methods. We hypothesized that thin-slice MBIR designed for brain CT could improve the detectability of acute ischemic stroke in the middle cerebral artery (MCA) territory. METHODS: Included were 41 patients with acute ischemic stroke in the MCA territory; they were seen at 4 medical centers. The controls were 39 subjects without acute stroke. Images were reconstructed with hybrid IR and with MBIR designed for brain CT at slice thickness of 2 mm. We measured the image noise in the ventricle and compared the contrast-to-noise ratio (CNR) in the ischemic lesion. We analyzed the ability of reconstructed images to detect ischemic lesions using receiver operating characteristics (ROC) analysis; 8 observers read the routine clinical hybrid IR with 5 mm-thick images, while referring to 2 mm-thick hybrid IR images or MBIR images. RESULTS: The image noise was significantly lower on MBIR- than hybrid IR images (1.2 vs. 3.4, p < 0.001). The CNR was significantly higher with MBIR than hybrid IR (6.3 vs. 1.6, p < 0.001). The mean area under the ROC curve was also significantly higher on hybrid IR plus MBIR than hybrid IR (0.55 vs. 0.48, p < 0.036). Sensitivity, specificity, and accuracy were 41.2%, 88.8%, and 65.7%, respectively, for hybrid IR; they were 58.8%, 86.1%, and 72.9%, respectively, for hybrid IR plus MBIR. CONCLUSION: The additional thin-slice MBIR designed for brain CT may improve the detection of acute MCA stroke.

Incidence and factor analysis of laryngohyoid fractures in hanging individuals-computed tomography study.

OBJECTIVES: Although laryngohyoid fracture indicates the applied neck pressure and is an important finding in hanging individuals, the reported rate varies widely and its true incidence remains controversial. We used computed tomography (CT) studies to investigate the incidence of laryngohyoid fracture in hanging individuals and identify factors contributing to such fractures. METHODS: Considered for inclusion in this study were 107 attempted or successful hanging individuals subjected to CT studies between 2005 and 2019. After excluding 19 whose images were inadequate for evaluation, 88 subjects were included. Body suspension was complete in 20, partial in 49, and unknown in 19; 54 (61.4%) individuals died. Two radiologists performed image analysis and recorded the presence and site of laryngohyoid fractures. Multiple logistic regression analysis was used for factor analysis of laryngohyoid fractures; it included the gender, the age (< or ≧ 40 years), the type of suspension (complete or incomplete), and the outcome (death or survival). RESULTS: Of the 88 subjects, 35 (39.8%) presented with laryngohyoid fractures on CT images; the superior horn of the thyroid cartilage was fractured in 32 (91.4%) of the 35. Age was the only factor significantly related to laryngohyoid fracture (odds ratio = 2.85, 95% confidence interval = 1.08-7.52). CONCLUSIONS: In hanging individuals, the incidence of laryngohyoid fracture on CT images was 39.8%. The superior horn of the thyroid cartilage was the most frequent fracture site. KEY POINTS: • The incidence of laryngohyoid fracture on CT images of hanging individuals was almost 40%; the superior horn of the thyroid cartilage was the most frequent fracture site. • In older hanging individuals, attention must be paid to laryngohyoid fractures on CT images.

Ornithine transcarbamylase deficiency that developed at the age of 19 years with acute brain edema.

Case: A 19-year-old man had nausea, diarrhea, and general malaise the day before requesting emergency transport to his former primary physician. The patient became restless and had tonic seizures after admission. The patient was transferred to our hospital as there had been no improvement in his level of consciousness. On arrival, cranial computed tomography showed generalized swelling, and blood ammonia concentration was ≥500 µg/dL. After admission, seizures recurred continually despite careful monitoring and increased doses of sedatives and antiseizure drugs. Dilated pupils and a flat electroencephalogram were evident on day 4 of admission, and the patient died on day 11. Ornithine transcarbamylase deficiency was diagnosed at postmortem based on fractionation of blood and urine amino acids and orotic acid. Outcome: Urea cycle disorders need to be treated urgently to prevent irreversible neurological damage when accompanied by hyperammonemia. Conclusion: In cases of hyperammonemia, early dialysis should be considered to reduce the ammonia level.